Flame transport in a heavy-duty diesel engine

A heavy-duty diesel engine has been constructed to provide full optical access to the piston bowl with a window forming the bottom of the “optical” piston. The engine is operated up to 1400 rpm, with peak firing pressure of up to 160 bar and IMEP levels of up to 20 bar. Fuel injection is accomplished with a common rail system and an externally driven high-pressure pump. Data were taken for cylinder pressure with synchronous recording of diesel flame ignition and combustion by means of a high-speed camera. The task of the project summarized in this paper was to evaluate flame and cylinder pressure data gained in this engine at part load and high-load operation. The focus of data evaluation was on identifying main flame transport mechanisms and relating them to simultaneously recorded rates of heat release.